Prof. Alexis Maizel Cell and Developmental biology

We primarily use Arabidopsis thaliana, a model plant which forms lateral roots from founder cells located deep in the primary root. The process starts with the de novo formation of stem cells, the asymmetric expansion of two abutting founder cells in the pericycle.

These founder cells share a common interface and expand along it, prefiguring the future dome-shaped lateral root primordium that grows out of the parental root. Accompanying the asymmetric growth, both nuclei migrate toward the common cell wall, and the cells divide asymmetrically. Failure to execute these steps leads to an aberrantly shaped lateral root or the complete arrest of lateral root growth.

Lateral root formation is a self-organizing process during which the founder cells invariably undergo first an asymmetric anticlinal division.  We showed that radial expansion of the founder cells and spatial accommodation by the overlying endodermis is essential for forming a lateral root and the first asymmetric cell divisions. We have made key discoveries about the role of the cell wall and the cytoskeleton in this process. We also have co-developed innovative methods to analyse the shape of cells.

Plants harvest energy from sunlight in their leaves to produce sugar. To support their growth, they must also forage for water and mineral nutrients with their roots. Designing better roots represents an under-explored way to increase yield in changing environmental and climate conditions, reduce fertilizer use and pollution, promote soil health and, ultimately, help people.

How to optimize root systems? This is not an easy question. Building more roots in an uncontrolled manner comes with construction and maintenance costs. Optimizing root systems, therefore, requires a basic understanding of the cellular mechanisms that control how and where new roots are formed.